Java XML How to - 使用 xpath 在 XML 文件中的节点列表中查找和添加/替换更多子项 [英] Java XML How to - Use xpath to find and add/replace more children to a Nodelist in an XML file

问题描述

我有一个 xml 文件 (ToThis.xml)，我正在用数组变量更新它.我正在使用 Xpath 更新到这个 xml 文件，但我只能更新第一个数组元素.见下文.

I have an xml file (ToThis.xml) that i am updating with array variables. Am using Xpath to update to this xml file but i can only update the first array element. see below .

xml 文件 (ToThis.xml) 我得到了什么

xml file (ToThis.xml) what i get

<?xml version="1.0" encoding="UTF-8"?><map xmlns="http://www.w3.org/2005/xpath-functions">
    <string key="ankomstDato">2020-08-20</string>
    <array key="planlagtAntallPerUndergruppe">
       <map>
          <number key="antall">67</number>
          <string key="kode">SLAKTEGRIS</string>
       </map> 
    </array>   
 </map>

我想得到的xml文件应该是这样的

xml file that i would like to get should be like this below

<?xml version="1.0" encoding="UTF-8"?><map xmlns="http://www.w3.org/2005/xpath-functions">
    <string key="ankomstDato">2020-08-20</string>
    <array key="planlagtAntallPerUndergruppe">
       <map>
          <number key="antall">67</number>
          <string key="kode">SLAKTEGRIS</string>
       </map> 
       <map>
          <number key="antall">4</number>
          <string key="kode">UNGSAU</string>
     </map>
    </array>   
 </map>

下面是代码的一部分，它让我得到第一个结果.注意(实际场景中的两个数组变量不是硬编码的，它们是动态分配的)

Below is portion of the code where it get me the first result. NOTE( The two array variable in real scenario are not hard coded they are assigned dynamically)

public void Write2XMLfile(){
    
            XPathFactory xpathFact = XPathFactory.newInstance();
        XPath xpath = xpathFact.newXPath();
    
        try {
    
            //
            String filepath = "E:/utils/Tothis.xml";
            //
    
            
            DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
            Document doc = docBuilder.parse(filepath);

            planlagtAntallPerUndergruppe_antall_value[0] = "67";                
            planlagtAntallPerUndergruppe_kode_value[0] = "SLAKTEGRIS";

            planlagtAntallPerUndergruppe_antall_value[1] = "4";                
            planlagtAntallPerUndergruppe_kode_value[1] = "UNGSAU";        
    
            //2.  planlagtAntallPerUndergruppe **************************
            System.out.println("\n This is second" );
            Node planlagtAntallPerUndergruppe = (Node) xpath.evaluate("/map/array[@key='planlagtAntallPerUndergruppe']/*", doc, XPathConstants.NODE);
            if(null != planlagtAntallPerUndergruppe) {
                NodeList nodeList = planlagtAntallPerUndergruppe.getChildNodes();
                for (int i = 0;null!=nodeList && i < nodeList.getLength(); i++) {
                    Node nod = nodeList.item(i);
                    if(nod.getNodeType() == Node.ELEMENT_NODE){
                        NodeList arrayElements_18 = (NodeList) xpath.evaluate("/map/array[@key='planlagtAntallPerUndergruppe']/*", doc, XPathConstants.NODESET);
                        //System.out.println("\n number of elements" + arrayElements_18.getLength());
                        for (int j = 0; j < arrayElements_18.getLength(); j++) {
                            //.  antall
                            Node antall = (Node) xpath.evaluate("(/map/array/map/number[@key='antall'])[1]", doc, XPathConstants.NODE);
                            antall.setTextContent(planlagtAntallPerUndergruppe_antall_value[j]);
                            // end antall
    
                            //.  kode
                            Node kode = (Node) xpath.evaluate("(/map/array/map/string[@key='kode'])[1]", doc, XPathConstants.NODE);
                            kode.setTextContent(planlagtAntallPerUndergruppe_kode_value[j]);
                            //System.out.println("\n\n antall: " + planlagtAntallPerUndergruppe_antall_value[j]);
    
                            // end kode                       
                        }                    
                    }
                         
                }
            }
    
            // end array planlagtAntallPerUndergruppe
            
    
            // write the content into xml file
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer transformer = transformerFactory.newTransformer();
            DOMSource source = new DOMSource(doc);
            StreamResult result = new StreamResult(new File(filepath));
            transformer.transform(source, result);
    
            System.out.println("Done Updating The Api_XML_Format.xml");
    
        } catch (ParserConfigurationException pce) {
            pce.printStackTrace();
        } catch (TransformerException tfe) {
            tfe.printStackTrace();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        } catch (SAXException sae) {
       

     sae.printStackTrace();
    } catch (XPathExpressionException xee) {
        xee.printStackTrace();
    }

    
  }

推荐答案

将收集到的数组作为参数传入 Write2XMLfile 方法

pass collected arrays into Write2XMLfile method as parameters

public void Write2XMLfile(String[] planlagtAntallPerUndergruppe_antall_value, String[] planlagtAntallPerUndergruppe_kode_value) {
   
   try {
       
         DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
         DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
         Document doc = dBuilder.newDocument();
         
         Element rootElement = doc.createElement("map");
         doc.appendChild(rootElement);

         Element mainString = doc.createElement("string");
         mainString.setAttribute("key", "ankomstDato");
         rootElement.appendChild(mainString).setTextContent("2020-08-20");
         
         
         Element array = doc.createElement("array");
         array.setAttribute("key", "planlagtAntallPerUndergruppe");
         rootElement.appendChild(array);
         

         if(planlagtAntallPerUndergruppe_antall_value.length>0){
             for (int i = 0; i < planlagtAntallPerUndergruppe_antall_value.length; i++) {
                Element map = doc.createElement("map");
                array.appendChild(map);
                
                Element number =  doc.createElement("number");
                number.setAttribute("key", "antall");
                map.appendChild(number).setTextContent(planlagtAntallPerUndergruppe_antall_value[i]);
                
                Element string =  doc.createElement("string");
                string.setAttribute("key", "kode");
                map.appendChild(string).setTextContent(planlagtAntallPerUndergruppe_kode_value[i]);
            }
         }

         TransformerFactory transformerFactory = TransformerFactory.newInstance();
         Transformer transformer = transformerFactory.newTransformer();
         transformer.setOutputProperty(OutputKeys.INDENT, "yes");
         transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
         DOMSource source = new DOMSource(doc);
         StreamResult output = new StreamResult(new File("output.xml"));
         transformer.transform(source, output);
         
      } catch (Exception e) {
         e.printStackTrace();
      }
}

输出.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<map>
  <string key="ankomstDato">2020-08-20</string>
  <array key="planlagtAntallPerUndergruppe">
    <map>
      <number key="antall">67</number>
      <string key="kode">SLAKTEGRIS</string>
    </map>
    <map>
      <number key="antall">4</number>
      <string key="kode">UNGSAU</string>
    </map>
  </array>
</map>

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